A cospobation



J. C. HAYES, JR 'HOT BLAST sTovE INSTALLATION 2 Sheets-Sheet '1 FiledApril 10. 1925 SDN QCM Nov. 9, 1926.

1,605,946 J. c. HAYES, JR

HOT BLAsT sTovs msTALm-rou Filed April 1o. 1925 2 sheets-sheet 2 figg.

Patented Nov. 9, i926.

i r r JOHN U. HAYES, JR., OF CHCAGO, ANY, 0F CHICAGO,

Application led April 10, 1925.

The present invention relates to hot blast stove installations.

More particularly the present invention relates to installationsinvolving hot blast stoves for blast furnaces. It is common practice toburn the blast furnace gas from blast furnaces in hot blast stoves, saidgas being washed prior to admission to said stoves. The washing of thegas entails a heat loss, and the use of the washed gas also is apt togive rise to a deposit 'of a mixture of lime and alkaline salts. Thisdeposit is more pronounced on settings with small combustion space thanwith modern settings. Unless the gas is dried, the gas mains have to beflushed regularly to clean out the sludge baked on the nozzles andv Theentrance of unevaporated apertures. water mist into the burners has theeffect, even in modern settings, of lowering the possible iiametemperature very materially.

For the purpose of illustration a plant may be assumed in which the gasfrom blast furnaces is washed for bot-h stove and boiler use. rlhe gascoming from the washer` at 72 degrees Fahrenheit is 'saturated withwater vapor or steam. rlhe amount of vaporized water at the abovetemperature may be taken to be 11.7 grains per cubic foot. The gas must,of course, be saturated, because it enters the washer at 300 degreesFahrenheit carrying about 30 grains of vap'orized water per cubic foot.In addition to a water vapor content corresponding to' saturation, itcontains excess moisture in the forniof small water globules or mist,which is carried over from the sprays in the gas washer and alsocondensed from the gas itself as the vapor in the gas is cooled down inthe washer. The 11.7 grains of moisture is steam. The moisture in excessof saturation at the temperature of the gas is unevaporated water andvapors from 0.5 to 2.0

grains per cubic foot. This water must beA evaporated, so that itslatent heat, as well as specific heat, is a detriment to combustion andlowers the flame temperature both in the stoves and in the boilers. Thedecrease in iiame temperature due to evaporation may amount to 10()degrees Fahrenheit or more.

Thek present invention contemplates the provision of means for dryingthe washed blast furnace gas pri-or to the admission of said washed gasto the stoves.

Serial No. 22.242.

An object of the present invention is to provide a blast furnaceinstallation of the type in which the blast furnace gas is burned in thehot blast stoves, which installation will have the advantage that theformation of sludge y0r other deposit will be minimized.

A. further object is to provide an improved system in which washed blastfurnace gas will be effectively dried before being admitted to hot blaststoves, whereby the efficiency of said stoves will be very materiallyimproved over present practice.

A further object is to provide an installation of the type in whichblast furnace gas is burned in hot blast stoves, in which installationthe exhaust gases from said stoves will be used for drying the washedblast furnace gas before said blast furnace gas is admitted to saidstoves.

A further object is to provide a blast furnace system in which thewashed blast furnace gas may be readily controlled.

A further'object is to provide an improved installation in which blastfurnace gas is used for supplying the hot blast stoves, whichinstallation will simplify the job of determining the location of leaksif any leaks should occur, of making repairs, and of by-passing theblast furnace gas in case any part of the installation should have to beshut down for repairs.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure 1 is a diagrammatic representation ofa blast furnace installation embodying the principles of the presentinvention;

Figure 2 is a view of a gas heater and drier used in the installationshown in Figure 1; and Y Figure 3 is a vertical sectional view takenalong the` plane indicated by the arrows 3 3 of Figure 2.

Referring first to Figure 1, the numeral 1 indicates a blast furnace,from whicl blast furnace gas is conducted through the conduits 2-2 tothe dust catcher 3. Said dust catcher 3 has communication with the gaswasher 4.- through the conduit 5, which may be controlled by the valve5. The gas washer t may have associated therewith the water seal 7 forpreventing the backflow of gas in case the blast furnace is shut down. Aconduit 8 controlled by the valve 9 prollt) vides conimunication betweenthe gas washer l1 and the water seal '7. Leading from the water seal 7are a pair of conduits 10 and 11, of which the conduit 10 Vis controlledby the valve 12 and the conduit 11 is controlled by the valve 13. Saidconduit 10 communicates with the conduit 14, which leads to tric boilerA conduit 15, controlled by the valve 15", is provided for by-passingblast furnace gas directly from the dust catcher 3 to conduit 10, whensuch by-passing required.

The conduit 11 vvprovides communication between the water seal 'Tand agas drier and heater indicated asa whole by the numeral 16. Said drier16 has the function of drying the which has been washed, whereby toprevent the deposit of sludge, as above referred to, and whereby toevaporate any entrained moisture in said gas. A conduit 17 leads fromthe drier 16 and has communication with the conduit 14 leading to theboiler 15, and also has communication (by way of conduit 17El controlledby the `valve 17) with the conduit 18, which connects with the blaststoves 19-19 through the pi es E20-20. A flue 21 conducts products ocombustion from the hot blast stoves 19--19, said flue being `connectedto the drier 16 through the conduit 22. As will be referred tohereinafter, the hot products of combustion from hot blast stoves areused for providing heat to dry the clean gases passing through saiddrier 16. After the products of combustion from the hot blast stoves19-19 lhave performed their heating functions in the drier 16, they areconducted through the conduit 23 to the stack 24. The conduit 17 isprovided with the valve 25 for stopping the flow of clean gas from theheater 16 to the conduit 18 when desired. The conduit 23 may be shut offfrom the stack 24 by means of the valve 26. Communication between theflue 21 and stack 24 may be controlled by the valve 27. The valve 28 isprovided in the conduit 22 to control the How of products of combustionto the heater16 for heating purposes.

The details of one form of heater 16 will now be described. The type ofheater shown in Figures 2 and 3 comprises an enclosure 29 provided withthe tubes 30-30. Said tubes connect with the chambers 31 and 32, ofwhich the chamber 31 is supplied by the conduit 11 and of which thechamber 32 delivers gas to the conduit 17. Said chambers should beprovided with manholes, whereby access may be had to the tubes d 3() forthe purpose of cleaning said tubes. Said chambers are also provided withthe drains 34, through which dirt may be removed.

Hot products of combustion from the hot blast stoves 19H19 are admittedto the enclosure 29 by way of the conduit 22. Said hot products ofcombustion take a oircuitous path through said enclosure 29, being dirccted along` said circuitous path by the baffle 35. The conduit 23provides communication from the interior ot' the enclosure 29 to thestack 2st.

During normal operation the valves 6, 9, 13, 17C, 25, 26 and 28 areopen, and valves 12, 15b and 27 are closed. Under these conditions gasfrom the blast furnace may pas.;` through the gas washer 4, water seal7, conduit 11, tubes B9- 30 of the heater 16, and 4pipe 17. From herepart of the gas may pass to the boiler .15 and the remainder et the gasmay pass through the conduit 16 to the hot blast stoves 19- -19.Products of combustion from the hot blast stoves 19-19 pass-through theconduit 22 to the interior of the enclosure 29 of the heater 16. Heatfrom said products of combustion is cornmunicated to the clean gaswithin the tubes {lO-30, eilectually drying said gases and`communieating' sensible .heat thereto. lVhen the `heater 16 is to beshut down, as, for eX- ample, for cleaning or repair, the valves 13, 25and 26 will be closed and valve 12 `will bc opened, whereby gas may bedirected from the dust catcher L1 and water seal 7 through the pipe 10to the boiler 15 and to the hot blast stoves 19-19 'Vhen it is desiredto cut out the Washer f1 and Water seal 7, valves 6 and 12 may be closedand valve 15b opened, under which conditions gas will be directedthrough the conduit 15 to the conduit 10.

By reason of the present invention sludge is deposited from the blastfurnace gas before it gets to the burners of the hot blast stove. `Saidsludge is deposited in the drier 16, which is easily cleaned, or iscarried along in the Aform of dry dust in ythe gas current. Theinstallation according to the .present invention offers an improvedetliciency over present practice, inasmuch as the burners in the stovesmay be kept in good condition for relatively long periods of time, sothat the time `consumed in shut downs is very materially reduced. Theentrance of unevaporated water mist in the gas as it enters thecombustion chamber is also very materially reduced.

Though a preferred embodiment of the present invention has beendescribed in detail, it will' be clear that many modifications willoccur to those skilled in the art. It is intended to cover all suchmodifications that fall within the scope of the appended claims.

lVhat is claimed is:

1. An installation including a blast furnace, hot blast stoves, meansfor conducting blast furnace gas from said blast furnace to said stoves,said means inelhdnga drier for said gas,..an`d means for conducting hotproducts of'combustion from said hot rblast stoves to said drier.

2. An installation comprising a blast furnace, hot blast stoves for saidfurnace, means 'for conducting blast furnace gas from said blastvfurnace to said stoves, said conducting means including a drier forsaid gas for causing,` the deposit of sludge and for raising thesensible heat of said gas, said drier being arranged for convenientcleaning, and means tor conducting products of combustion from saidstoves to said drier.

S. In combination, a, blast furnace, hot blast stoves lor cooperationwith said furnace, a pair of parallel paths for conducting blast furnacegas from said furnace to said stoves, one ot' said paths including adrier for said gas, and means for conducting hot products oi" combustionfrom said stoves to said drier for drying the gas in said stoves and forraising the sensible heat thereof, said drier being capable of readycleaning, and valve means for controlling said parallel paths.

4. Means for improving the eliiciency of blast furnace installations,comprising, in

combination with the usual blast furnace,

hot blast stoves and a heater for the gas delivered from said furnace tosaid stoves, said heater being readily cleanable and being heated byproducts of combustion from said stoves.

Signed at Chicago, illinois, this 7 day of April, 1925. i

JOHN C. HAYES, JR.

